This invention relates to fluid pressure regulators generally, and specifically to an O-ring damped fluid pressure regulator, particularly, suited for (but not limited to) use in agricultural irrigation systems.
It is well known to use fluid pressure regulators in irrigation systems in order to provide constant outlet pressure over a wide range of inlet pressures. The need for such regulators is particularly acute in low pressure systems because a slight variation in pressure along a system operating at low pressure causes a much greater variation and discharge than the same system operating at high pressure.
The assignee of this invention currently manufactures and sells a fluid pressure regulator of the flow through type, having an inlet at one end of the tubular housing and an outlet at the other end of the tubular housing. A plunger seat is fixed within the housing and is adapted to be engaged by a tubular plunger which is spring biased away from the seat (in the direction of fluid flow) so that under normal conditions, maximum flow through the regulator is permitted. In the event of a pressure surge, the plunger is moved by back pressure within a diaphragm chamber against the action of the spring (and against atmospheric pressure), toward the regulator seat to thereby decrease the flow through the regulator until the pressure is reduced, and the plunger returns to its wide open normal position under the influence of the spring.
The above-described regulator has experienced "chatter", or excessive vibration, when a rapid and high pressure surge is experienced. More specifically, sudden flow into (and then out of) the diaphragm chamber causes rapid reciprocation of the plunger which creates excessive vibration within the regulator, and which may cause damage to the internal components of the regulator.
The present invention incorporates an O-ring or other suitably shaped resilient ring and an associated bleed groove arrangement at the downstream end of the plunger, which serves as a damper by restricting the rapid flow of liquid, e.g., water, into and out of the diaphragm chamber, thereby preventing undesirable chatter and potential damage to the regulator.
In a first exemplary embodiment of the invention, the objective is achieved by forming the plunger with a radially outwardly facing groove or damper chamber at its downstream end, and into which a resilient ring (such as an O-ring) is loosely fitted. This downstream end of the plunger moves within a reduced diameter bore portion of the regulator housing which, in turn, communicates with a diaphragm chamber formed in a larger diameter portion of the housing. The diaphragm chamber surrounds the plunger and is further defined by a flexible diaphragm fixed at an inner radial edge to the plunger and at an outer radial edge to a stationary sleeve in the housing. The outer diameters of the radially outwardly extending flanges which form the O-ring groove or damper chamber, and the loose fit of the O-ring within the groove, permit water to flow past the groove and into the diaphragm chamber. When a pressure surge is experienced by a regulator, fluid pressure builds up in an upstream direction, causing the plunger to move toward the seat to reduce flow in the inlet portion of the regulator. During this time, the O-ring expands outwardly in the same upstream direction to momentarily seal against the entry of additional water into the diaphragm chamber. An axial bleed groove is provided in the bore of the downstream section of the tubular regulator housing, however, which communicates between the outlet end of the regulator and the damper chamber so that liquid may bleed out of the damper chamber and thus prevent a hydraulic lock. Upon subsequent decrease in pressure, movement of the plunger away from the seat in a downstream direction causes fluid to be expelled from the diaphragm chamber as well as the damper chamber, causing the O-ring to expand outwardly in the downstream direction to momentarily seal against the exit of additional water out of the damper chamber. In this way, regulation of fluid flow and consequent movement of the plunger takes place slowly, in a damped manner.
In an alternative embodiment of the invention, the groove and O-ring are fitted within an annular groove formed in the housing bore, rather than in the plunger, and the axial bleed groove is formed in the plunger, but the device otherwise functions in the same manner.
Thus, in its broader aspects, the present invention provides a fluid pressure regulator comprising:
a tubular housing having a fluid inlet at one end thereof and a fluid outlet at an opposite end and a first through passageway therebetween; PA1 an open-ended tubular plunger mounted for reciprocal movement in the first fluid passage of the housing, the plunger having a flow control end and a piston end, said piston end having a piston surface and a flexible diaphragm extending radially between said piston surface and said housing; PA1 a seat in the through passageway including a seating surface located axially upstream of the plunger and adapted to be engaged by said flow control end of the plunger; and PA1 a damper downstream of the piston end of the plunger, the damper including a resilient ring located in a damper chamber communicating with said fluid outlet.
In another aspect, the invention provides a fluid pressure regulator comprising a housing, a plunger slidable in the housing, a seat adjacent one end of the plunger and a diaphragm chamber adjacent the other end of the plunger, the diaphragm chamber being defined in part by the other end of the housing, another end of the plunger and a diaphragm connected therebetween, the improvement comprising a damper chamber at the other end of the plunger, the damper chamber having a damper element therein for regulating flow into and out of the diaphragm chamber.
In still another aspect, the invention provides a fluid pressure regulator comprising a housing having a first fluid passageway extending through the housing from an inlet end thereof to an outlet end thereof; and annular seat in the housing; a tubular plunger having a flow control end, the plunger adapted to move toward and away from the seat, a variable flow regulating passage being defined by the flow control end and the seat; biasing means for exerting force on the plunger in a direction away from the seat; a diaphragm chamber located toward an end of the plunger opposite the flow control end, the diaphragm chamber adapted to receive fluid under pressure to thereby act on the plunger so as to move the plunger toward the seat as a function of fluid pressure in the outlet end of the housing; and, a resilient damper element within the damper chamber for damping fluid flowing into and out of the diaphragm chamber.
Other objects and advantages of the fluid pressure regulator in accordance with the invention will become apparent from the detailed description which follows.